This invention relates generally to feeder and header drives of agricultural combines, and more particularly, to a reversible hydro-mechanical variable speed drive which allows varying the speed of the feeder and header independent of engine speed.
Currently, feeder and header drives for agricultural combines typically utilize a variable ratio belt and chain drive system for varying the operational speed of the feeder and header.
However, variable ratio belt and chain drives typically used for power transmission to feeders and headers have limited speed ranges and less than desirable speed control, and can suffer from reliability problems, namely slippage in the instance of belt drives, and breakage in the instance of both drives, particularly when transmitting significant levels of power under varying loads such as when crop population and loads are large and/or weeds are encountered.
Therefore, what is sought is a hydromechanical drive for a feeder and header which provides a significant increase in power capability compared to known feeder and header drives, a wider speed range, better speed control, and a built-in reverse capability.
A variable speed, reversible drive for rotating elements of a feeder and a header of an agricultural combine which provides many of the sought after capabilities is disclosed. The variable speed drive includes a first rotatable power input, a second rotatable power input, and a planetary gear arrangement or set including a first rotatable input, a second rotatable input, and a rotatable output, the rotatable elements of the feeder and the header being connected to the rotatable output of the planetary gear arrangement for rotation thereby. The drive includes a forward clutch having a rotatable input and a rotatable output selectably engageable for joint rotation, and a brake or reverse clutch having a rotatable input selectably engageable with a fixed element such as a case of the drive for limiting or preventing rotation of the brake input, the first rotatable input of the planetary gear arrangement being connected to the rotatable output of the forward clutch and to the brake input for rotation therewith, the input of the forward clutch being connected to the first power input for rotation therewith, and the second rotatable input of the planetary gear arrangement being connected to the second power input for rotation therewith.
In operation, when the first power input and the second power input are rotated while the brake is disengaged, the input and the output of the forward clutch can be engaged to rotatably connect the first power input to the first rotatable input of the planetary gear arrangement for rotating the rotatable elements of the feeder and the header in a first rotational direction at a speed that can be varied by varying a speed of the rotation of the second power input. Alternatively, the brake can be engaged while the input and the output of the forward clutch are disengaged for rotating the elements of the feeder and header in a second rotational direction opposite the first rotational direction, the speed of rotation in this direction also being variable by varying the speed of rotation of the second power input.
Preferably, the first power input is connected to a power source rotating at a substantially constant speed such as an internal combustion engine of the combine, and the second power input is connected to a power source rotatable at a variable speed, such as a variable speed hydraulic motor or the like connected to a hydraulic pump for receiving pressurized hydraulic fluid therefrom, one of the hydraulic motor or pump having a displacement variable for varying the rotational speed of the hydraulic motor.